Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b7570132652be91…

MALICIOUS

PDF

68.4 KB Created: 2021-04-08 20:42:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: e01001b2072d33436310653498b82235 SHA-1: fe5eb4e56283d58078939e6ef347ab2267e0eb45 SHA-256: 4b7570132652be91ce930f03df93190cd097bf2dc359043c8614ba3761b4075c
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript and is flagged by ML classifiers and ClamAV as malicious. It also functions as a link farm, directing users to multiple suspicious URLs, including one hosted on disposable infrastructure. The embedded JavaScript likely exploits a vulnerability to execute a payload or redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://klm3fg.grhosting.cz/sites/default/files/webform/files/mimixinaxeralowevowijut.pdf In PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/nuxikovevevugodir.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/wozupidojenebimovom.pdfIn PDF document text
    • http://www.pacificsportfraservalley.com/sites/default/files/webform/joxelivoresilawefuxeli.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/95859103094.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/66890294103.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/nufideleze.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/58234525485.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/98565071062.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/xojisipet.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=learn+autocad+3d+pdfPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/85064040694.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/85266863194.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/jelozubunumi.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d062.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD062 5044 bytes
SHA-256: 940fd41ea9d8a4f52c9702915a58e99b0b09951445a89d01988581dae11e7c38
font_01_sfnt_off0000e1a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1A2 10512 bytes
SHA-256: ffd49c6f1e9b009debf8bb70b710dbaae07cd8b277fbb0fa436bfa7ca4d6e9d4

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